A psychologist In the hit BBC TV show, Killing Eve, Villanelle, a psychopathic assassin, tells Eve, a security service operative, “You should never call a psychopath a psychopath. It upsets them.” She then pouts her lip in an imitation of someone feeling upset.

Most people think they know what a psychopath is: someone who has no feelings. Someone who probably tortured animals for fun when they were little. But here are five things you probably didn’t know about psychopaths.

1. There’s a bit of a psychopath in all of us.

Psychopathy is a spectrum, and we are all somewhere on that spectrum.

If you’ve ever shown a lack of guilt or remorse, or not felt empathy with someone, or you’ve charmed someone to get what you want (remember that last job interview?), then you’ve displayed a psychopathic trait. Maybe you’re fearless in certain situations or you’ve taken big risks – also psychopathic traits.

2. Psychopaths are not all “psycho”.

Patrick Bateman in American Psycho and Hannibal Lecter in Silence of the Lambs are typical portrayals of psychopaths in popular culture. While it’s true that most serial killers are psychopaths, the vast majority of psychopaths are not serial killers.

Psychopaths comprise about 1% of the general population and can be productive members of society.

Their lack of emotions, such as anxiety and fear, helps them to stay calm in frightening situations. Experiments have shown that they have a reduced startle response.

If someone gave you a fright while you were watching a horror movie, you would probably show an “exaggerated startle response” – in other words, you’d jump out of your skin. Psychopaths react far less intensely in such fear-evoking situations. If anything, they remain calm. This can be a useful trait if you’re a soldier, a surgeon or in the special forces.

Psychopaths can also be very charming (even if only superficially) and they have the ability to confidently take risks, be ruthless, goal-oriented and make bold decisions.

This makes them well suited to environments like Wall Street, the boardroom and parliament. Here, psychopaths are more likely to be making a killing than killing.

That is, they focus on increasing their short-term mating opportunities and number of sexual partners rather than investing a lot of effort in long-term mating, parenthood and life stability.

This strategy is linked to increased risk taking and selfishness. Also, cities offer psychopaths better opportunities for finding people to manipulate. They also offer greater anonymity and hence a reduced risk of being detected.

4. Female psychopaths are somewhat different.

Although male and female psychopaths are similar in many ways, some studies have found differences.

Some psychologists argue that female psychopathy is sometimes diagnosed with borderline personality disorder, instead – characterised by poorly regulated emotions, impulsive reactions and outbursts of anger. This might explain why most studies show that rates of psychopathy are lower in females.

Our latest research shows that female psychopaths seem to prefer to date non-psychopathic men in the short-term, perhaps as a plaything or to allow easy deception and manipulation.

But for long-term relationships, a female psychopath will be looking for a fellow psychopath. Eventually, birds of a feather, flock together.

5. Psychopaths do have feelings … well, some feelings.

While psychopaths show a specific lack in emotions, such as anxiety, fear and sadness, they can feel other emotions, such as happiness, joy, surprise and disgust, in a similar way as most of us would.

So while they may struggle to recognise fearful or sad faces and are less responsive to threats and punishments, they can identify happy faces and they do respond positively when getting rewarded.

However, while winning a fiver might make you happy, a psychopath would need a bigger reward to perk them up.

In other words, they can feel happy and motivated if the rewards are high enough. Of course, they can also get angry, especially in response to provocation, or get frustrated when their goals are thwarted.

So Villanelle is right, to some extent. You can hurt a psychopath’s feelings, but probably different feelings and for different reasons.